CVCT involves couples being counselled together when considering an HIV test, testing together, and having post-test counselling together.

Approximately 150,000 couples have received CVCT in Lusaka, Zambia.

Data presented to the conference showed that CVCT reduced HIV incidence in couples and that the efficacy of HIV treatment as prevention was boosted in couples having CVCT.

CVCT was shown to be highly cost-effective.

"Couple counselling should be a priority in ART clinics in Africa," said the researchers. "Our research showed that it greatly increases the prevention effectiveness and cost-effectiveness of HIV treatment."